Thursday, May 13, 2021

Quantitative and Qualitative

Cory Doctorow's latest LOCUS column analyzes the difference between quantitative and qualitative measurements and the pitfalls of depending solely on the former:


He begins with examples from the COVID-19 pandemic. The University of Illinois at Urbana-Champaign became the epicenter of a COVID outbreak as a result of putting too much faith in an epidemiological model produced by "a pair of physicists." (The article doesn't mention why they were chosen to work the calculations instead of specialists in epidemiology.) The predictions didn't take into account the variables of human behavior, the "qualitative" element. The article cites contact tracing as another example of similar problems. Regardless of how accurate the math based on the data may be, do the infected people trust contact tracers enough to supply reliable data? Those who work with quantitative elements such as statistics and mathematical models have to restrict their research to elements that can be quantized. As Doctorow puts it, "To do math on a qualitative measurement, you must first quantize it, assigning a numeric value to it," a difficult and dubiously reliable process. (E.g., "How intense is your pain?" I never quite know how to answer that question on a scale of one to ten.)

Quantitative disciplines, as he summarizes the issue, "make very precise measurements of everything that can be measured precisely, assign deceptively precise measurements to things that can’t be measured precisely, and jettison the rest on the grounds that you can’t do mathematical operations on it." He compares this process of exclusion to the strategy of the proverbial drunk searching for his car key under the lamppost—not because that's where he lost it, but because that's where the light is.

Doctorow applies the principle to an extended discussion of monopolies, price-fixing, collusion, and antitrust laws. As an example of the potential injustice generated by "treating all parties as equal before the law," he mentions the designation of Uber drivers as "independent contractors." When treated as equivalent to giant corporations, those drivers are forbidden to "form a collective to demand higher wages," because that's legally classified as "price-fixing."

Although Doctorow doesn't mention writers, the same absurdly imbalanced restrictions can be made to apply to them. If an authors' organization promulgates a model contract and puts pressure on publishers to adhere to it, that's prohibited as "collusion" in restraint of trade.

While, according to Doctorow, "Discarding the qualitative is a qualitative act. . . . the way you produce your dubious quantitative residue is a choice, a decision, not an equation," that doesn't mean quantitative measures are useless or inherently evil. The quest for objectivity has its legitimate role—"just because we can’t rid ourselves of the subjective, it doesn’t follow that we must abandon the objective." Reliable empirically based outcomes result from balancing the quantitative and the qualitative components of the available evidence.

Margaret L. Carter

Carter's Crypt

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